Quantitative acoustic contrast tomography for studying fungal growth and toxicity

Abstract

Methods for ultrasonically imaging a heterogeneous 3D-cell population without physically probing are provided. The method can comprises: pulsing ultrasound waves having a wave frequency of about 10 MHz to about 2 GHz through a lens rod, wherein the lens rod focuses the ultrasound waves onto the cell population via a concave lens-head (e.g., comprising sapphire), and wherein the cell population is positioned on the reflective surface such that the ultrasound waves are reflected back to the lens-head; receiving the reflected waves through the lens head and the lens rod at a signal receiver; scanning the lens-head across multiple points in the x,y plane; and at each point in the x,y plane, moving the lens-head in a z-direction such that a signal is received at multiple intervals in the z-direction for each point in the x,y plane.

What is claimed: 
     
       1. An ultrasonic imaging module, comprising:
 a pulser; 
 a piezoelectric transducer configured to be activated using the pulser to generate ultrasound signals having wave frequencies between 10 MHz and 2 GHz; 
 a lens rod attached to the piezoelectric transducer such that the ultrasound signals travel through the lens rod; 
 an unltrasonic reflecting sheet: 
 a concave lens-head positioned within the lens rod and movable therein, wherein the concave lens-head is configured to focus the ultrasound signals traveling through the lens rod on a specimen positioned on the ultrasonic reflecting sheet, wherein the ultrasonic reflecting sheet has an acoustic impedance greater than an acoustic impedance of the specimen; 
 an acoustic signal receiver attached to the piezoelectric transducer to receive reflected ultrasound signals from the specimen; and 
 an ultrasonic micrograph generator. 
 
     
     
       2. The module of  claim 1 , wherein the lens head comprises a sapphire lens. 
     
     
       3. The module of  claim 2 , wherein the lens rod is protected with a brass casing. 
     
     
       4. The module of  claim 1 , wherein the ultrasound waves have a wave frequency of about 50 MHz to about 300 MHz. 
     
     
       5. The module of  claim 1 , wherein the ultrasound waves have a wave frequency of about 85 MHz to about 115 MHz. 
     
     
       6. The module of  claim 1 , further comprising a switch electrically connected to the piezoelectric transducer. 
     
     
       7. The module of  claim 1 , wherein the acoustic impedance of the ultrasonic reflecting sheet is about three times the acoustic impedance of the specimen. 
     
     
       8. The module of  claim 1 , further comprising a switch that toggles between the pulser and the acoustic signal receiver. 
     
     
       9. The module of  claim 1 , where in the ultrasonic micrograph generator comprises:
 an acoustic signal amplifier that receives electrical signals from the acoustic signal receiver; and 
 a Hilbert filter and a tomographic compiler that receive electrical signals from the acoustic signal amplifier and produce acoustic ultrasonic micrographs. 
 
     
     
       10. An ultrasonic imaging module, comprising:
 a pulser; 
 a piezoelectric transducer configured to be activated using the pulser to generate ultrasound signals having wave frequencies between 10 MHz and 2 GHz; 
 a lens rod attached to the piezoelectric transducer such that the ultrasound signals travel through the lens rod; 
 a concave lens-head positioned within the lens rod and movable therein, wherein the concave lens-head is configured to focus the ultrasound signals traveling through the lens rod on a specimen positioned on a reflective surface; 
 an acoustic signal receiver attached to the piezoelectric transducer to receive reflected ultrasound signals from the specimen; 
 a switch that toggles between the pulser and the acoustic signal receiver; 
 an ultrasonic micrograph generator; and 
 an ultrasonic reflecting sheet positioned in front of the concave lens-head and suitable for mounting a specimen, wherein the ultrasonic reflecting sheet has an impedance greater than an acoustic impedance of the specimen. 
 
     
     
       11. The module of  claim 10 , where in the ultrasonic micrograph generator comprises:
 an acoustic signal amplifier that receives electrical signals from the acoustic signal receiver; and 
 a Hilbert filter and a tomographic compiler that receive electrical signals from the acoustic signal amplifier and produce acoustic ultrasonic micrographs.